Frontend senior test

Serokell is a fast-growing, fully-remote software development company that works on innovative solutions for complex problems. We’re packed full of adventurous, curious, and inclusive folks that want to build cutting-edge software with modern technologies like functional programming.

We’re searching for a Frontend Developer that would help us create new web pages and applications for us and our clients.


  • Participate in the development of different web applications.
  • Create one-off pages for our website in collaboration with the marketing.
  • Solve issues/bugs connected to the website.
  • Develop our shop using the Shopify platform.


Candidates should have 2+ years of experience working in production with:

  • SASS (CSS3). You should be familiar with things like adaptive design, @use imports, mixins, and the methodology of BEM.
  • Modern JavaScript (ECMA2015). You should have solid knowledge with a least an ECMA2015 level of understanding.
  • TypeScript. You should be familiar with things like generics, type guards, and discriminated union types.
  • React/pReact or other libraries for building user interfaces. You should be familiar with things like functional components, component lifecycle & nesting, working with states, and SSR components.
  • SQL. You should be familiar with things like PostgreSQL syntax and migrations (Prisma).

You will get bonus points if:

  • You have a good understanding and experience of backend development.
  • You know how protocols, software, and algorithms used work under the hood. For example, network protocols (TCP, HTTP), Node.js, and binary search trees.
  • You are a confident user of complex JavaScript libraries and external APIs.
  • You are a perfectionist in a good way. If “pixel perfect” characterizes your work, if you organize your work in fine-grained patches with descriptive commit messages, we want you at Serokell.
  • You have experience with Haskell, Rust, or Elixir.
  • You are familiar with either RemixJS or NextJS.
  • You have the capacity to set up a module bundler with custom TSX and SASS bounding.
  • You are comfortable working on isomorphic web apps.

Tech stack

  • We prefer TypeScript over vanilla JavaScript to implement any frontend logic.
  • React library.
  • Our typical database choice is PostgreSQL.
  • For our shop, we are going to use Shopify.
  • In applications for our clients, we often implement both frontend and backend components. Backend development is usually done in Haskell. Frontend development may involve the usage of domain-specific JS libraries and external web APIs.
  • We typically use Nix to deploy and package any software we develop.